the present invention relates to a burner block for mounting a burner within a furnace containing a melt. More particularly, the present invention relates to such a burner block in which primary and secondary recirculation zones are formed beneath a flame, emanating from the burner, to distort and displace the flame towards the melt. In another aspect, the present invention relates to a method of heating a melt within a furnace in which a flame produced by a burner is distorted and displaced towards the melt by primary and secondary recirculation zones located between the flame. In still another aspect, the present invention relates to the combination of the furnace, the melt, the burner and the burner block.
Melts, ferrous and non-ferrous, are heated within a furnace by burners designed to burn fuel in an oxidant, either air or oxygen enriched air or high purity oxygen. The melt is heated by a projected flame produced by the burner. As can be appreciated, heat is transferred not only to the melt, but also the ceiling of the furnace. In order to increase the heat transfer to the melt, it is known in the prior art to direct the projected flame towards the melt. For instance, in U.S. Pat. No. 4,909,733 a prior patent of the inventor herein, a burner or fuel jet is undershot by a rate enhancing gas consisting of oxygen or oxygen enriched air to produce combustion over a wide area and to draw the flame downwardly towards the melt by producing a low pressure field beneath the flame. In U.S. 5,199,867, also a prior patent of the inventor herein a burner is provided with a divergent, high momentum oxidant jet beneath a fuel jet to produce a fan-shaped divergent flame downwardly drown by the high velocity oxidant jet.
The foregoing patents are particularly desirable in glass furnaces and exhibit particularly desirable global combustion characteristics for all combustion applications. It is to be appreciated though that the direction of the flame in such patents cannot be dynamically adjusted in applications in which the level of the melt changes over time. As will be discussed, the present invention provides apparatus and methodology in which the degree to which the flame is displaced towards the melt is automatically adjusted to vary as the heat-accepting interface of the thermal load or melt varies.